Automatic lock nut



April 4, 1939. I I J, SCHINDEL 2,152,977

AUTOMATI C LOCK NUT Filed Aug. l, 1936 INVENTOR v(/oH/v SCH/NDH UNITED fs'lfTE-g 4 claims. (ci. 151;-2)

This invention relates to the automatic locking of nuts on screw threads particularly on revolvingshafts, studs, chucks, and the like subject to lvibrations and where the position of the nut is subject to frequent rotative adjustment along the length of the screw thread.

The object of my invention is to provide a nuty which automatically locks itself in any position of rotative adjustment along the length of the screw thread and is held from accidental rota? tion out of its adjusted position in disregard to vibrations and directional changes of rotation.

The automatic lock nut of my invention is es-v pecially useful in the adjustment of tension springs of power driven chucks such as are employed in screw driving, nut setting and stud driving attachments for portable electric or other poweroperated rotary tools where quick adjustments are essential on account 4 .of frequent changes in torque requirements due to different sizes of screws and nuts being driven.

One important feature of my, invention is that the locking of the nut to the screw is not aiected by clamping the screw threads, which practice 4 tends to distort, destroy, and'pe'rmanently wear out the screw threads and also prevents free adjustment, of the nutvalong thel screw threads..

4In accordance with my` invention the' nut is vprovided with a spring biased locking disc having y a lug or key slidable in a key-way out lengthwise in the shaft on which the nut is mounted. "This discis also slidably mounted with respect to the the nut is forcibly turned in the direction desired. The projections on the llocking disc' ride vinto and out of the depressions in the nut and this action is repeated until the nut' has reached the desired .position of adjustment along the screw thread. Byhaving a large number of depressionsin the body of 'the nut, the nut can be turned only a few degrees before reaching a new locking position.

The lock vnut of my invention is a complete and unitary structure and as such can be screwed on and off the' shaft element or other support with In the accompanying drawing showingthe preferred embodiment of my invention:

Fig. 1 shows a screw driving attachment for a portable electric tool in longitudinal section and embodying the automatic lock nut of my 5 invention;

Fig. 2 is a similar view of the lock nut and its associated shaft element on a larger Scale;

Fig. 3 is a face view of the nut on its shaft with portions broken away and in section, re- 10 spectively, to show the spring biased locln'ng disc and the cooperating projections and depressions which holdthe nut in its various positions of adjustment; s

Fig. 4 is an edge view of the nut, partly in l5 section, to show the knurling which may be employed to facilitate turning the nut;

Fig. 5 is a similar view showing a nut with a smooth edge and provided with one or'more holes to receive a pin for turning the nut; 20

Fig. 6 is an edge view of the spring element employed with the nut in Figs. I to 3;

Fig. 7 isa similar view of a corrugated thin spring washer which may be employed for the f spring element in the lock nut assembly; 25

Fig. 8 is a face view of said corrugated washer;

Fig. 9 is an edge view of a ilat spring washer which may be employed for the spring element;

Fig. 10 is a face view of said washer; and

Fig. 11 shows a modified form of locking disc 30 to be hereinafter described.

Inthe drawing, I indicates the gear casing of the screw driving attachment. 'I'his gear casing is detachably fastened as by screwsrto the front end of the motor casing of 'the portable electric 35 or other power driven rotary tool with which the attachment is employed. The casing l has a forwardly extending tubular boss 2 in which the spindle 3 of the tool is journaled as shown in Fig. 1. 'Ihe spindle is driven by the motor of 40 the tool through a gear reduction in the casing l as in devices of this character.

The spindle 3 extends beyond the boss 2 andis provided with a clutch member I- at its outerend. This clutch member is slidably, but non- 45 rotatably mounted on the spindle .by suitable -means such as a key 5 and balls 6 as shown.

The clutch member I cooperates with a clutch member 1 fixed on a driven chuck shaft 8 which is axially aligned with the spindle 3 and carries 50 a screw driving bit 9 at its outer end as shown. The shaft -8 is slidably and rotatably supported by the. spindle 3 by havingthe inner end portion of the shaft extending into the spindle which which it is employed.

is made hollow to receive the shaft end. The v56 latter 'engages a spring means III located in the hollow of the spindle, which spring means serves to normally force the shaft outwardly from the spindle to separate the .clutch members 4 and 1 when the tool is removed from the work. These clutch members `are engaged by pressing the tool against the work and said clutch members are provided on their opposed surfaces with cooperating radial clutch teeth I I, I2 which teeth when interlocked, connect the shaft 8 to the spindle 3 for'rotatlon thereby.

lA coiled spring I3 surrounds the spindle between the clutch member 4 and a nut I4. Said nut is mounted on the screw threaded portion I5 of the spindle adjacent the inner end of the spring I3 and serves to hold the spring I3 against the clutch member 4. The nut is also employed to adjust the tension of this spring to regulate the torque at which the clutch members -4 and 1, while engaged, will automatically release the drive of the spindle on the shaft 8 when the screw being set resists the turning of the shaft.

-The clutch teeth are provided with beveled or inclined side edges whereby the clutch members may have rotative slippage when releasing. 'I'he clutch member 4 in this action is forced rearwardly against the spring I3, the key 5 riding in its slot I6 in the spindle 3. The outward movement of the clutch member 4' by the spring I3 is limited by the key 5 engaging the forward end of its slot I6. This holds the clutch member 4 in position to receive the clutch member 'I when the clutch members are engaged on forcing the tool against the work.

'I'he nut I4 in accordance with my invention has a body portion I1 provided at one side with a chamber I8 in which is located a locking disc I9 having an inwardly extending radial lug 29 providing a key for engagement with a longitudinally. extending key-way 2l cut in the threaded portion I5 of the spindle 3 -or other shaft element on which the nut may be mounted. v

This key holds the disc I8 against rotation with the nut, yet permits the disc to be carried along with the nut as the nut is turned along the screw threaded portion I5 and also permits lateral sliding movement of the disc with respect to the nut in the chamber I8.

A retaining washer 22 closes the outer end of the chamber I8 and provides aseat for a spring.

The spring element, as shown in Figs.-v 1f vto 3' and 6, is in the .form of one turn of ro'ii'rid'steel wire and serves ft'normally press thelocking disc I9 against-"the nut body at the inner'face of its chamber I8. The disc I9 is provided on its inner side with a number of circumferentially spaced projections vor protuberances 24 which cooperate with similarly disposed depressions or sockets 25 in the nut body as shown in Figs. 2 and ,3. When the projections seat in the depressions, the nut I4 will be held against accidental rotation on its shaft element 3 and be xed in its position of adjustment along the screw threaded portion I5 of said shaft element.

To adjust the nut along the screw, the nut is forcibly turned in the direction desired and the projections 24 by reason of their semi-circular form ride out of the depressions and reenter the next adjacent depressions as the .nut is turned. This produces a clicking sound and the nut can be stopped in any position of its adjustment along the screw` and be held in its adjstdposition by the interlocking of the projections with equal Vin number` or the depressions may outnumber the projections depending upon the nicety oi' the adjustment required. In the parjticular embodiment shown three projections 24 are provided on the locking disc I9 and six depressions 25, are provided in the nut body I1. This gives a considerable number of adjusted positions for the nut in each complete revolution.

The retainer 22 is held in closed relation with respect to the chamber I8 in any manner desired. In the drawing, I have shown the chamber provided with a shoulder to seat the retainer and with the louter edge of the chamber pressed over the outer side of the retainer to hold it in place.

To facilitate turning the nut it may be knurled about its outer cylindrical surface as indicated at 26 invFig. 4 or if the nut `has a plain cylindrical surface a number of holes 21 may be provided in the nut whereby a pin may be engaged with the nut for turningit. 'I'he nut may also have hexagonal or other non-circular shape to facilitate turning it. A knurled nut is used in the smaller sizes of screw or nut driving devices which t of hand adjustment to set the disc 29 is employed to mount the balls and the other disc 39 is employed to take the pressure of the spring element 23 and provide the necessary clearance for the balls to turn in the adjustment of the nut.

In lplace of the spring wire element 23 I may employ a corrugated thin spring washer 3I as shown in Figs. 7 and 8 or a flat dish-shaped split spring washer 32 as shown in Figs. 9 and 10.

The screw driving attachment shown in Fig. 1 is enclosed in an outer casing 33 which screws its inner end on the boss 2 and is provided at its outer end with a spring pressed sleeve 34 providing a guide and centering means for the drlv` l ing bit 9. The latter has a releasable pull-out connection with the chuck shaft 8 as shown.

For a nut driving attachment, the construction will be arranged to include a nut engaging socket which would be connected to the forward Vend of the chuck shaft 8. The spring I0 in sepatary structure which maybe screwed on and off the shaft element 3 as shown in the broken lines in Fig. 2. The key-way 2| in the shaft element extends through the end of the shaft as indicated in this gure. When lthe nut is turned off of tension regardless of vibration.

arcas?? the screw threaded portion of the shaft, the locking disc retains its splined connection with the shaft and the nut may be slid laterally off the non-threaded portion oi' the shaft. In applying the nut, the key of the locking disc is engaged with the key-way 2|, and the nut is slid on the shaft until the screw threaded portion is reached, whereupon the nut is turned to 'engage the threaded portion. v The automatic lock nut of my invention adaptable for use in any installation4 where it is desired to adjust a spring tension and hold the The nut is especially applicable to power driven screw and nut setting devices for portable tools in which the vibrations are more or less severe as the clutch members release many times in the use of such tools in a days work and at a relatively high speed of rotation.

The details of construction shownpand described may be variously changed and modied without-departing from the spirit and scope oi' my invention, except as pointed out in the appended claims.

I claim as my invention:

l. In combination with the releasing clutch oi a screw or nut driving device for portable power op erated rotary tools, of a.r spring for regulating the torque at which vthe clutch releases in the operation o! the device, a nut for adjusting the tension of said spring, a shaft for rotating' the clutch and having a screw threaded portion to mount the nut, a spring biased iocking disc splined on said shaft, said spline extending through one end of the shaft, co-acting means on the disc and the nut and acting automatically on turning the nut in either direction for normally holding the nut in any of its positions of rotative adjustment along the threaded portion of said shaft, and a retainer carried by the nut ior holding the discin assembled relation with the nut and movable therewith as a unit on and ofi of said shaft. f. 2. The combination with a support having a screw threaded portion, of acoiled spring assoelated with said supporta nut mounted on the jections and depressions on the disc and the nut.

respectively, for normally holding the nut against turning in either direction in any of its positions of rotative adjustment on the threaded portion of, said support, said nut having a chamber to .re-

ceive the disc and its spring, and a retainer carried by the nut for holding the disc and its spring in said chamber, whereby the parts as a unit may be moved on. and oil of the shaft with said nut.

3. An automatically locking nut of the character described, comprising as a unitary structure a body portion having formed therein a chamber opening outwardly through one side of said nut body, a locking disc and a spring element located within the confines of said chamber being inserted into said chamber through the open end thereof. with the disc against the wall of the nut body at the base of said chamber, a retainer carried by the nut body within said chamber and in xed position adjacent theouter open end ofsaid chamber for holding the spring against the disc, said spring forcing the disc against the nut body at the base of the chamber, and interlocking projections and depressions on the opposed surfaces of the disc and the nut body for normally holding the nut body against turning in either ydirection with respect to the disc, the latter having a key to nt in a keyway in the mounting provided for the nut, said projections and depresrable clutch members with interengageable clutch v teeth, of a spring for regulating the torque at which the clutch teeth when engaged release in the operation of the ciutch, a nut for adjusting the tension of said spring, a shaft for rotating the clutch members and having a screw threaded portion to mount the nut, and means interconnected with the nut and the shaft and acting automatically on turning the nut for normally holding the nut against rotation in 'either direction in. any of its positions of rotative aiustment on the threaded portion of said shaft, said means being carried by the' nut and movable therewith along the'shaft and on and oii the same as a unit.

l .ronNscnrNmm 

